class Solution {
public:
    int climbStairs(int n) {
        int dp[50] = {0};
        dp[1] = 1;
        dp[2] = 2;
        for (int i = 3; i <= n; ++i)
            dp[i] = dp[i - 1] + dp[i - 2];
        return dp[n];
    }
};

// link : https://leetcode.cn/problems/climbing-stairs/?envType=study-plan-v2&envId=top-100-liked